Threaded element with carrier part deforming locking key



p 6, 1966 R. NEUSCHOTZ ETAL 3,

THREADED ELEMENT WITH CARRIER PART DEFORMING LOCKING KEY Filed April 20, 1964 INVEN RS 2205527 Nsusc 7-2 CULLEN 3 JAMEs ATTORNEY United States Patent 3 270 792 THREADED ELEMElilT WITH CARRIER PART DEFORMING LOCKING KEY Robert Neuschotz, Beverly Hills, and Cullen E. James,

Southgate, Califl, assignors to Newton Insert Company,

Los Angeles, Calif., a corporation of California Filed Apr. 20, 1964, Ser. No. 361,085 3 Claims. (Cl. 151--23) This invention relates to an improved locking key structure for retaining a threaded insert or other threaded element in a carrier part, and particularly for locking the element against unscrewing rotation relative to the part.

In my Patent Number 2,855,970 issued October 14, 19.5 8 on Insert Having Frictionally Retained Key Which Upsets Threads of Base Member, I have disclosed an externally threaded element having at least one key which is received within a groove extending generally axially along the outer surface of the element, and is adapted to be driven axially farther into that groove to form a lock between the threaded element and a carrier part into which the element is screwed. To attain this locking action, the key has an axially inner reduced thickness portion which is received and frictionally retained within the groove, but is thin enough to avoid interference with initial screwing of the element into the carrier part. The key also has a thicker axially outer locking portion which carries a locking projection adapted to bite or dig into the carrier pant thread upon the axial driving movement of the key, to form an interlock therewith.

The elements and keys of the present invention are of the above discussed general type, but incorporate improvements in the keys for facilitating the axial driving of the keys, and increasing the reliability of the locking action. More particularly, the invention relates to the construction of the keys in such relation with respect to the threaded element itself as to control the flow of the deformed carrier part material during the key driving action, with the purpose of minimizing the resistance to axial movement of the key, preventing-distortion of the key during driving, and assuring ultimate arrival of the locking projection of the key at its final locking position in optimum condition for attaining a most effective locking act-ion. To attain these purposes, we prefer to so form the key and groove that, in the final locking condition of the device, substantial clearance is left between the locking projection and the side walls of the groove. By virtue of this clearance relationship, there is provided between the key and one or both of the side Walls of the groove a space or gap of substantial size, into which the material of the carrier part may be extruded or forced during a' key driving operation. Preferably, gaps of this type are provided at both sides of the locking portion of the key, and the key has a leading essentially radially extending cutting edge adapted to cut through the threads of the carrier part and spread the material of those threads laterally for reception within the two mentioned gaps. It is found desirable that the clearance continue through the entire radial extent of the locking projection, and be equal to at least about one-third (preferably at least about one-half) of the width of the projection itself.

The above and other features and objects of the invention will be better understood from the following detailed description of the typical embodiment illustrated in the accompanying drawing, in which:

FIG. 1 is a side View, partially broken away, of a threaded insert constructed in accordance with the invention;

FIG. 2 is a fragmentary elevation on line 22 of .FIG. 1;

FIG. 3 is a fragmentary axial section through the 3,270,792 Patented Sept. 6, 1966 right-hand locking key of FIG. 1, as it appears after being driven to its locking position;

FIG. 4 is a fragmentary plan view of the lefthand key groove of FIG. 1, with the key removed;

FIG. 5 is a fragmentary plan view taken on line 5-S of FIG. 1;

FIG. 6 is a fragmentary section taken on line 6-6 of 'FIG. 3;

FIG. 7 is a fragmentary transverse section taken on line 77 of FIG. 3;

FIG. 8 is a perspective view showing one of the locking keys as it appears separately; and I FIG. 9 is a view similar to FIG. 7 of a variational form of the invention.

The threaded insert 10 shown in FIG. 1 has an essentially tubular body 11, typically formed of steel or other metal, and having internal threads 12 into which a mating externally threaded screw is to be connected to secure this screw to a carrier part 13 through the medium of insert 10. Externally, the insert has threads 14, which may be standard threads having a 60 degree angle between their opposite side faces, but preferably having a modified minor diameter to form cylindrical modified minor diameter surfaces 15 extending axially between successive turns of external threads 14.

The carrier part 13 has a passage containing internal threads 16 which mate with external threads 14 of the insert 10, and have similarly modified minor diameter surfaces at 17. The outer surface of the carrier part may be planar, and is represented at 18 in FIGS. 1 and 2, and is disposed transversely of the axis 19 of insert 10 and carrier lpart threads 16. The opening in the carrier part may be countersunk at its axially outer end, to provide an annular cfrustro-conical countersink surface 20.

Extending along two opposite sides of the insert body, there are formed two diametrically opposed axially extending grooves 21 within which a pair of locking keys 2 2 are received. These grooves may be of identical cross-section, as illustrated in FIGS. 4 and 5, and with that cross-section being uniform along the entire axial length of the insert. To define the cross-section of the grooves more specificially, it is noted that each groove may have an inner planar wall surface 23 which extends directly parallel to axis 19 of the insert, and may be perpendicular to a radial line 24 extending radially outwardly from axis 19. These two inner wall surfaces 23 of the two grooves are typically parallel to one another.

Extending generally radially outwardly from wall 23, the opposite sides of each groove 21 are defined by a pair of side walls 25 (FIG. 4), having first radially outwardly converging portions 26, and second mutually parallel portions 27. Thus, these side walls form together a groove of dovetail cross-section within which an associated one of the keys 22 may be slidably received, The inner converging portions 26 of the groove side walls are received primarily, and desirably almost entirely, within the diameter of modified minor diameter surfaces 15 of the insert threads. The parallel portions 27 of the groove side walls project outwardly beyond the minor diameter surfaces 15, and therefore are actually formed in the threads 14, and are of course interrupted axially between successive turns of those threads. The two side wall surfaces 27 of one of the grooves 21 may lie in the same planes as do the corresponding surfaces of the other groove.

Each key 22 has a radially inner planar surface 28 which abuts against and is slidable axially along the inner wall surface 23 of the corresponding groove 21. The key may be considered as consisting of an axially inner initial mounting portion 29 and an axially outer portion 30. Portion 29 is frictionally received and retained in groove 21, while portion 30 initially projects axially outwardly as seen in FIG. 1, and is therefore not received in the groove until ultimately driven to the FIG. 3 position. Portion 29 has a radial thickness 31 (FIG. 1) which is slightly less than the radial thickness or dimension 32 (FIG. 4) of the tapering dovetail portion of associated groove 21, to thereby be received entirely within that dovetail portion. As will be apparent from FIG. 7, and from FIGS. 2, and 8, the portion 29 may be of rectangular transverse section, being defined at its outer side by a planar surface 33 extending parallel to inner surface 28, and being defined along its opposite side edges by two parallel axially extending side surfaces 34. At the intersection of surfaces 34 and surface 33, there are formed axially extending corners or edges 35 on portion 29, which engage tapering dovetail surfaces 26 of the groove in a manner positively locating portion 29 of the key within the groove. The portion 29 is a very tight frictional fit within the groove, effectively retaining the key by friction in the FIG. 1 position of outward projection from the insert, until the keys are forceably driven axially by a hammer or other driving or pressing tool. Radially outer surface 33 of portion 29 of the key is located far enough radially inwardly to avoid contact with the internal threads 16 of carrier part 13 as the insert is screwed into the carrier part.

Axially outer portion 30 of the key may be considered as having a first radially inner portion 36 which is in effect a continuation of portion 33 except that portion 36 is slightly reduced in width at 37, so that parallel side surfaces 38 of portion 36 are slightly closer together than are the corresponding side surfaces 34 of portion 33. Portion 36 is, however, a sufficiently close fit within the dovetail portion 26 of groove 21 to be effectively guided for axial sliding movement therein,

In addition to its portion 36, portion 30 of the key forms and integrally carries a locking projection 39 which projects radially outwardly beyond the diameter of minor diameter surfaces 15, and which preferably projects outwardly far enough to have its outer surface 40 disposed at approximately the major diameter of external threads 14. Projection 40 may be of essentially rectangular transverse cross-section, as seen in FIGS. 5 and 7, being defined at its opposite sides by a pair of parallel side walls 41 disposed parallel to opposite side surfaces 34 and 38, but substantially closer together than are either of the latter pairs of surfaces. Outer surface 40 of the locking projection 39 may be disposed parallel to surface 28, and per pendicular to side surfaces 41. The axially outer end 42 of the key may be defined by a transverse end surface as indicated at 42, in FIG. 1, disposed transely of axis 19, and spaced axially outwardly a substantial distance beyond the transverse annular end surface 43 of the insert body.

At its axially inner end, the locking projection 39 is preferably tapered in the manner shown, to form two planar opposite side surfaces 43 which may be perpendicular to surfaces 23, 28 and 40, and which converge toward one another as they advance axially inwardly to form a sharp axially facing cutting edge 44. This edge 44 may extend essentially radially of axis 19, and preferably substantially directly radially of that axis. Edge 44 may be approximately aligned with, and preferably substantially exactly aligned with, the plane of outer end surface 43 of the insert body.

To attain the advantage of the present invention, locking projection 39 is made sufficiently narrow relative to the spacing dimension 46 between groove walls 27, to leave substantial clearance (circularly about axis 19) between this projection and the groove walls 27, in the locking position of the key. While it is contemplated that perhaps this clearance could be provided more at one side of the projection than the other, it is preferred that the projection be located midway between the groove walls, to leave equal clearance gaps or spaces 47 at opposite sides of the projection, between surfaces 27 and 41. The clearance should continue through the entire radial extent of projection 39. At each point through that entire radial extent the total clearance at both sides of the projection is desirably at least about one-third, and preferably at least about one half (for best results as much as of the width 45 of projection 39 at that point.

To now describe the manner of installation of the present insert, assume first of all that the insert is in the condition illustrated in FIG. 1, with the two keys 22 mounted as shown in the'insert, and effectively retained by friction against unwanted movement axially further into or axially out of grooves 21. This insert assembly, including body 11 and the two keys, is screwed into carrier part 13 to the position illustrated, and during such installation may be turned by manipulation of keys 22, which are in effect integral With body 11. The depth to which the insert is screwed into the carrier part is determined by engagement of the outer extremities of corner portions 48 (FIGS. 1 and 8) of edges 44 of the keys with countersink surface 20 of the carrier part. The parts are so dimensioned that, when this engagement occurs, outer surface 43 of the insert is in a predetermined preferably slightly inset relationship with respect to surface 18 of the carrier part.

After the insert has reached this position of engagement with the countersink surface, keys 22 are driven axially relative to the insert and carrier part to the locking position of FIG. 3. As the keys move axially, edges 44 cut int-o the material of threads .16 of the carrier part and split each of those threads into two portions which are then received at opposite sides of key portion 39. The carrier part thread material thus split is received within the two gaps or passages 47 at opposite sides of key portion 39 (FIG. 5). FIG. 6 shows at 49 the manner in which this material of the carrier par-t, after being split, is deformed downwardly into passages 47. Such reception of the deformed material within these passages facilitates the axial driving movement of the keys, and in addition increases the effectiveness of the locking action. Further, the cutting action of edges 44 additionally enhances the axial movement of the keys, and prevents distortion of the key which might otherwise result.

FIG. 9 shows a slightly variational form of the invention which may be considered as identical with the form shown in FIGS. 1 through 8 except for certain changes in the cross sectional configuration of key 22a and the recess 21a within which it is received. More particularly, in FIG. 9 the angularly extending dovetail portions 26a of the groove side walls may be disposed at less abrupt angles than are the corresponding surfaces 26 in FIG. 4, so that the inner dovetail portions of the recesses are not as wide as in FIG. 4. Further, the locking projection 39a in FIG. 9 (corresponding to projection 39 of the first form of the invention) may have side Walls 41a which converge gradually and progressively as they advance radially outwardly, rather than being disposed directly parallel to one another. These side surfaces 41a of locking projection 39a are however spaced sufiiciently from the opposed side wall surfaces of the groove to leave clearance spaces which, through the entire radial extent of portion 39a, have the dimensional characteristics heretofore discussed in connection with the first form of the invention. That is, the dimensions are such that the sum of the widths of the two clearance spaces (circularly about the axis of the insert) at the radially inner extremities of the spaces, is equal to at least about one-third (preferably at least one-half, and for best results as much as 100%) of the circular width of projection 39a at that same radially inner location; and similarly the sum of the widths of the two gaps at their radially outer extremity and at each intermediate point has the same relationship to the projection width at the same location.

We claim:

1. An element comprising a body having external threads disposed about an axis and adapted to be screwed into a passage in a carrier part, and having additional threads for attachment to another member, said body having a groove formed therein and extending generally axially through said external threads, a key received in said groove and adapted to be driven axially relative to said body to a locking position to lock the element in said carrier part, said key having an axially inner first portion received and frictionally retained in the groove at the location of some of said external threads and which is thin enough radially to avoid interference thereby with screwing of said element into said passage, said key having a second portion projecting axially outwardly beyond said groove and accessible for engagement by a tool to drive the key axially within the groove, .said second portion forming a locking projection which extends radially outwardly farther than said first portion to cut into the material of said carrier part when the key is driven axially, said groove having an outwardly narrowing dovetail shaped radially inner portion containing and slidably retaining and confining said first portion of the key and having a radially outer portion which is located outwardly beyond and does not contain said first portion of the key, said outer portion of the groove being defined by essentially parallel approximately radially extending opposite side walls positioned to receive said locking projection circularly therebetween in said locking position thereof, said side walls being spaced apart far enough to leave clearance space circularly between said locking projection and said side walls at each point through the entire radial extent of said projection, equal to at least about one-third of the width dimension of said projection circularly about said axis at that point, said locking projection having opposite side surfaces extending substantially parallel to said side walls of the groove and being located for reception approximately midway between said side walls so that said clearance space forms two approximately equal Width gaps at opposite sides of the projection, said projection having an axially inner end tapering axially to an essentially sharp cutting edge which extends essentially radially outwardly with respect to said axis, said second portion of the key having a radially inner portion which forms essentially a continuation of said first portion of the key but is slightly narrower than said first portion and wider than said projection.

2. An element comprising a body having external threads disposed about an axis and adapted to be screwed into a passage in a carrier part, and having additional threads for attachment to another member, said body having a groove formed therein and extending generally axially through said external threads, at key received in said groove and adapted to be driven axially relative to said body to a locking position to lock the element in said carrier part, said key having an axially inner first portion received and retained in the groove at the location of some of said external threads and which is thin enough radially to avoid interference thereby with screwing of said element into said passage, said key having a second portion projecting axially outwardly beyond said groove and accessible for engagement by a tool to drive the key axially (within the groove, said second portion forming a locking projection which extends radially outwardly farther than said first portion to out into the material of said carrier part when the key is driven axially, said groove having a radially inner portion containing said first portion or the key and having a radially outer portion which is located outwardly beyond and does not contain said first portion of the key, said groove being defined by spaced opposite side walls having radially inner portions forming said inner portion of the groove and received at opposite sides of said first portion of the key, said side walls having radially outer portions defining said outer portion of the groove and positioned to receive said locking projection circularly therebetween in said locking position thereof, said radially outer portions of said groove side walls being in more closely spaced relation than are said inner portions of the walls to give said groove an undercut cross section for retaining the key therein, and said outer portions of the walls being spaced apart far enough to leave clearance space circularly between said locking projection and said outer portions of said side walls, at each point through the entire radial extent of said projection, equal to at least about one-third of the width dimension of said projection circularly about said axis .at that point, said second portion of the key having a radially inner portion which forms essentially a continuation of, and is essentially aligned with, said first portion of the key, but is slightly narrower than said first portion and wider than said projection, and is receivable between said radially inner portions of said side walls of the groove when the key is driven axially.

3. An element comprising a body having external threads disposed about an axis and adapted to be screwed into a passage in a carrier par-t, and having additional threads for attachment to another member, said body having a groove formed therein and extending generally axially through said external threads, a key received in said groove and adapted to be driven axially relative to said body to a locking position to lock the element in said carrier part, said key having an axially inner first portion received and retained in the groove at the location of some of said external threads and which is thin enough radially to avoid interference thereby with screwing of said element into said passage, said key having a second portion projecting axially outwardly beyond said groove and accessible for engagement by a tool to drive the key axially within the groove, said second portion forming a locking projection which extends radially outwardly farther than said first portion to cut into the material of said carrier part when the key is driven axially, said groove having a radially inner portion containing said first portion of the key and having a radially outer portion which is located outwardly beyond and does not contain said first portion of the key, said groove being defined by spaced opposite side walls having radially inner portions forming said inner portion of the groove and received at opposite sides of said first portion of the key, said side walls having radially outer portions defining said outer portion of the groove and positioned to receive said locking projection circularly therebetween in said locking position thereof, said radially outer portions of said groove side walls being in more closely spaced relation than are said inner portions of the walls to give said groove an undercut cross section for retaining the key therein, and said outer portions of the walls being spaced apart far enough to leave clearance space circularly between said locking projection and said outer portions of said side walls, at each point through the entire radial extent of said projection, equal to at least about one-third of the width dimension of said projection circularly about said axis at that point, said radially outer portions of said groove walls extending essentially parallel to one another and approximately radially, said locking projection having opposite side surfaces extending substantially parallel to said outer portions of the groove 'walls and being located for reception approximately midway between said side Walls so that said clearance space forms two approximately equal Width gaps at opposite sides of the projection.

References Cited by the Examiner UNITED STATES PATENTS 2,855,970 10/1958 Neusohotz 1512-3 

1. AN ELEMENT COMPRISING A BODY HAVING EXTERNAL THREADS DISPOSED ABOUT AN AXIS AND ADAPTED TO BE SCREWED INTO A PASSAGE IN A CARRIER PART, AND HAVING ADDITIONAL THREADS FOR ATTACHMENT TO ANOTHER MEMBER, SAID BODY HAVING A GROOVE FORMED THEREIN AND EXTENDING GENERALLY AXIALLY THROUGH SAID EXTERNAL THREADS, A KEY RECEIVED IN SAID GROOVE AND ADAPTED TO BE DRIVEN AXIALLY RELATIVE TO SAID BODY TO A LOCKING POSITION TO LOCK THE ELEMENT IN SAID CARRIER PART, SAID KEY HAVING AN AXIALLY INNER FIRST PORTION RECEIVED AND FRICTIONALLY RETAINED IN THE GROOVE AT THE LOCATION OF SOME OF SAID EXTERNAL THREADS AND WHICH IS THIN ENOUGH RADIALLY TO AVOID INTERFERENCE THEREBY WITH SCREWING OF SAID ELEMENT INTO SAID FERENCE THEREBY WITH SCREWING OF SAID ELEMENT INTO SAID AXIALLY OUTWARDLY BEYOND SAID GROOVE AND ACCESSIBLE FOR ENGAGMENT BY A TOOL TO DRIVE THE KEY AXIALLY WITHIN THE GROOVE, SAID SECOND PORTION FORMING A LOCKING PROJECTION WHICH EXTENDS RADIALLY OUTWARDLY FARTHER THAN SAID FIRST PORTION TO CUT INTO THE MATERIAL OF SAID CARRIER PART WHEN THE KEY IS DRIVEN AXIALLY, SAID GROOVE HAVING AN OUTWARDLY NARROWING DOVETAIL SHAPED RADIALLY INNER PORTION CONTAINING AND SLIDABLY RETAINING AND CONFINING SAID FIRST PORTION OF THE KEY AND HAVING A RADIALLY OUTER PORTION WHICH IS LOCATED OUTWARDLY BEYOND AND DOES NOT CONTAIN SAID FIRST PORTION OF THE KEY, SAID OUTER PORTION OF THE GROOVE BEING DEFINED BY ESSENTIALLY PARALLEL APPROXIMATELY RADIALLY EXTENDING OPPOSITE SIDE WALLS POSITIONED TO RECEIVE SAID LOCKING PROJECTION CIRCULARLY THEREBETWEEN IN SAID LOCKING POSITION THEREOF, SAID SIDE WALLS BEING SPACED APART FAR ENOUGH TO LEAVE CLEARANCE SPACE CIRCULARLY BETWEEN SAID LOCKING PROJECTION AND SAID SIDE WALLS AT EACH POINT THROUGH THE ENTIRE RADIAL EXTENT OF SAID PROJECTION, EQUAL TO AT LEAST ABOUT ONE-THIRD OF THE WIDTH DIMENSION OF SAID PROJECTION CIRCULARLY ABOUT SAID AXIS AT THE POINT, SAID LOCKING PROJECTION HAVING OPPOSITE SIDE SURFACES EXTENDING SUBSTANTIALLY PARALLEL TO SAID SIDE WALLS OF THE GROOVE AND BEING LOCATED FOR RECEPTION APPROXIMATELY MIDWAY BETWEEN SAID SIDE WALLS SO THAT SAID CLEARANCE SPACE FORMS TWO APPROXIMATELY EQUAL WIDTH GAPS AT OPPOSITE SIDES OF THE PROJECTION, SAID PROJECTION HAVING AN AXIALLY INNER END TAPERING AXIALLY TO AN ESSENTIALLY SHARP CUTTING EDGE WHICH EXTENDS ESSENTIALLY RADIALLY OUTWARDLY WITH RESPECT TO SAID AXIS, SAID SECOND PORTION OF THE KEY HAVING A RADIALLY INNER PORTION WHICH FORMS ESSENTIALLY A CONTINUATION OF SAID FIRST PORTION OF KEY BUT IS SLIGHTLY NARROWER THAN SAID FIRST PORTION AND WIDER THAN SAID PROJECTION. 